1. Field of the Invention
Embodiments of the disclosure relate to a digital hologram image reproducing device capable of reproducing a three-dimensional (3D) image using a digital hologram image and a synchronization control method of the digital hologram image reproducing device.
2. Discussion of the Related Art
Recently, studies on three-dimensional (3D) images and image reproduction technologies are being actively carried out. 3D image media are real image media of new concept providing high-level visual informations and thus is expected to lead to the next generation image display devices. The existing two-dimensional (2D) imaging systems provide a plane image. On the other hand, 3D imaging systems may be referred to as an ultimate image display technology because they show real image information of an object to observers.
As methods for reproducing the 3D image, a stereoscopy method, a holography method, an integral imaging method, etc. have been studied and developed. Out of the methods, the holography method reproduces the 3D image through a hologram image reproduced using a laser and thus can implement the 3D images without glasses.
The holography method records an interference signal obtained by the superposition of light (i.e., object wave) reflected from an object and light (i.e., reference wave) having the interference and reproduces the interference signal. The object wave, which is scatted by hitting on an object using a laser beam with high coherence, meets the reference wave incident in a direction different from the object wave, thereby forming interference fringes. The recording of the interference fringes on a photographic film is called a hologram. The interference fringes are formed by the interference generated when the object wave meets the reference wave, and amplitude information and phase information of the object are recorded on the interference fringes. The interference fringes include intensity information and phase information of the light waves. The intensity information is recorded as a contrast between interference fringe patterns of the interference fringes, and the phase information is recorded as a distance between the interference fringe patterns. The holography method irradiates a reference beam onto the interference fringes and reproduces the interference fringes recorded on the hologram as the 3D image.
Computer generated hologram (CGH) for storing, transmitting, and image processing a hologram pattern using a computer was developed using various methods. Systems for displaying a computer generated hologram of a motion image as well as a still image have been developed.
The computer generated hologram system may calculate the interference fringes using the computer and may produce a hologram interference fringe image. The computer generated hologram system transmits data of the hologram interference fringe image to a spatial light modulator (SLM). When the reference beam is irradiated onto the SLM, hologram interference fringe patterns displayed on the SLM are reproduced as the 3D image. The SLM may be implemented as a liquid crystal display panel. A pixel size of a SLM panel has to decrease and a screen size of the SLM panel has to increase, so as to improve the quality of the 3D image. However, because a reduction in the pixel size has a technological limit, a plurality of liquid crystal display panels may be attached to one another on the same plane and may be individually driven, so as to increase the screen size.
When the liquid crystal display panels are attached to one another on the same plane, polarities of data voltages supplied to the same line of the individually driven liquid crystal display panels may not be synchronized. Namely, the polarities of the data voltages on the same line of the liquid crystal display panels may be different from one another. When the polarities of the data voltages on the same line of the liquid crystal display panels are reversed, the computer generated hologram system adversely affects the quality of the 3D image. For example, a 3D hologram reproduction image may be reversed up and down.